Oxygen, antioxidants: Does the oxygen that keeps us alive slowly kill us too?

a reply to: Bedlam

I only mentioned wine because it has antioxidants in it. A glass a day is good for you.

I'll look into what you said though, if it checks out I'll adjust.

What is a flavanoid besides a type of antioxidant?

originally posted by: ignorant_ape
a reply to: pikestaff

no - 100% oxygen will not kill you - divers use 100% oxygen for decompression stops at < 10m [ less that 2 bar absolute pressure ]

I thought divers used a mixture of Oxygen and an inert gas like Helium? which is why their voices sound hilarious?
I still think pure oxygen at 15 PSI will kill, its called oxygen narcosis?
The astronaughts in the pre Apollo test missions for the 3 man re-entry module used pure oxygen, but at 3 PSI I believe, been a long time since!

a reply to: pikestaff

without getting my book of tables and dive comp out :

oxygen toxicity is determined by its partial pressure

PP0 [ partial pressure - oxygen ] limit for safe operations = 1.50

the calculations for PPO at depth is beyond the scope of this post [ transpate - i will have to dig out my textbook to explain it coherently ]

but at depth there are 2 conflicting factors to dive gasses :

oxygen toxicity

nitrogen narcosis

the simplified version = upto 50m depth - you can use a mix called nitrox - which is air with aditional oxygen to reduce the egffects of nitrogen narcosis -

deeper than 50m - both nitorgen narcosis AND oxygen toxcicity have to be considered

so thats why helium is used for deep diving

the mosrt common deep gas is known as trimix - and a " typical bottom gas " fpr a 75m dive will have just 10% oxygen and 30% helium

this mix cannot be used above a certain depth - which i forget - so you end up with a decent mix - a nottom mix and a deco [ decompression ] mix

yup - thats 3 serpeate cylinders and regulators - that have to be swapped at set times [ or you die ]

PS - a lot of people confuse :

nitrogen narcosis - which happens at depth - and simply put makes you do silly things

with

decompression trauma - which is caused by nitogen bubbles forming in the blood stream during rapid ASCENT and leads to injury // death

but bottom line - i stand my my earlier post - 100% oxygen can be used as a deco gas at < 10m

originally posted by: Rasalghul
a reply to: Bedlam

I only mentioned wine because it has antioxidants in it. A glass a day is good for you.

I'll look into what you said though, if it checks out I'll adjust.

What is a flavanoid besides a type of antioxidant?

You got resveratrol in there, although probably not enough to do serious sirtuin stimulus. It also, for whatever reason, helps out your LDL/HDL balance.

a reply to: Bedlam
Oh. Well thanks, science irritates me Im by no means dumb but science talk tends to get complex and I just zone out. Unless it's health related then I want to know everything. Astronomy is cool and rocket science is like the apex of scientific achievement, so that is interesting. But thanks.